Mechanical extraction case for pasty products in stick form

ABSTRACT

It is disclosed a mechanical extraction case for pasty products in stick form, comprising a tubular housing ( 2 ), a slider ( 8 ) designed to engage a pasty product in stick form ( 9 ) and slidably engaged in the tubular housing ( 2 ), and a lead screw ( 4 ) coaxially extending along the housing ( 2 ) through a through opening ( 11 ) formed in the slider ( 8 ) and operatively engaging the slider itself to translate it along the housing ( 2 ) following a rotation imparted to the lead screw ( 4 ). Radially interposed between the lead screw ( 4 ) and the slider ( 8 ) is a rotation-preventing element ( 13 ), locked against rotation in the housing ( 2 ) and slidably engaging the slider ( 8 ).

FIELD AND BACKGROUND OF THE INVENTION

The present invention pertains to a mechanical extraction case for pasty products in stick form, of the type comprising the features set out in the preamble of claim 1.

In particular, the present invention can apply to manufacture of lipsticks and similar beauty products to which particular reference will be made in the progress of the present specification.

It is known that lipsticks and similar beauty products in stick form are usually packed in cases combined with a screw mechanism enabling the pasty product to be easily pushed out and pulled in without being obliged to directly touch it with the hands.

For instance, a case is known from document FR 2833816 which comprises a tubular housing in which a slider engaging the stick of pasty product is slidably accommodated. Rotatably in engagement with one end of the tubular housing is a lead screw coaxially extending in the tubular housing and operatively engaged through the slider. Through rotation of the lead screw by an operating knob disposed at the end of the tubular housing, the slider moves along the housing itself bringing the stick between a rest position at which it is held in the housing, and a use position at which it projects from the housing end opposite to the operating knob.

To prevent the slider from being driven in rotation by the screw, longitudinal ribs are disposed on the inner wall of the tubular housing and they slidably engage respective radial cuts provided in the circumferential edge of the slider itself.

Recent market trends have shown the requirement for use of transparent plastic material in making cases for lipsticks and similar beauty products, to enable the user to directly see the stick of pasty product inside the case.

The Applicant has however noticed that use of transparent material in making the above described cases would make the same aesthetically unacceptable, above all in the cosmetic sector where the aesthetic appearance constitutes a decisive factor in the product appreciation by the users.

In accordance with the present invention, the Applicant has realized the possibility of achieving important improvements in the capability of appreciating the quality of the packaging, through elimination of the ribs and/or other discontinuities from the inner surfaces of the tubular housing, which ribs are required so as to prevent the slider from rotating. In particular, according to the present invention, the necessity to arrange said ribs is overcome by providing a rotation-inhibiting element radially interposed between the screw and slider.

SUMMARY OF THE INVENTION

In more detail, it is an object of the present invention to provide a mechanical extraction case for pasty products in stick form, comprising the features set out in the characterizing portion of claim 1 and/or in one or more of the following claims.

Further features and advantages will become more apparent from the detailed description of a preferred but not exclusive embodiment of a mechanical extraction case for pasty products in stick form, in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

This description will be set out hereinafter with reference to the accompanying drawings, given by way of non-limiting example, in which:

FIG. 1 shows a case made in accordance with the present invention, diametrically sectioned along line I-I in FIG. 2;

FIG. 2 shows the case axially sectioned along line II-II in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the drawings, a mechanical extraction case for pasty products in stick form in accordance with the present invention has been generally identified with reference numeral 1.

Case 1 comprises a substantially cylindrical tubular housing 2 of circular section having a first end 2 a suitable for engagement with a removable closing cap 3. Rotatably in engagement with a second end 2 b of the tubular housing 2 is a lead screw 4 coaxially extending along housing 2 over part of the longitudinal, extension of the latter.

The lead screw 4 has a threaded portion 5 extending from a base portion 6 carrying an operating knob 7, externally opening from the second end 2 b of housing 2, and a handgrip portion 7 a to enable screw 4 to be driven in rotation.

Slidably inserted in the tubular housing 2 is a slider 8 designed to engage a lipstick or other pasty product in stick form denoted at 9 by a chain line in FIG. 1. In more detail, slider 8 engages one base end 9 a of stick 9 by a base 10 substantially shaped as a circular dish, possibly provided with a peripheral rim 10 a axially projecting towards the first end 2 a of the housing itself. Screw 4, and more specifically the threaded portion 5 thereof, crosses a central through opening 11 of slider 8. At the central opening 11, slider 8 has at least one radial projection 12 operatively engaging the threaded portion 5 of the lead screw 4. In the embodiment shown, two diametrically opposite radial projections 12 are provided which have each a substantially prismatic attachment portion 12 a rigidly connected to base 10 of slider 8 and a cylindrical portion 12 b extending from the attachment portion 12 a to be radially fitted between two threads of the threaded portion 5.

A rotation imparted to screw 4 by means of the operating knob 7 causes an axial movement of slider 8 and consequently of stick 9 between a rest position at which stick 9 is fully contained in housing 2, and a use condition at which stick 9 projects from the housing itself at least partly by its end 9 b opposite to the base end 9 a.

Radially interposed between slider 8 and screw 4 is a rotation-inhibiting element 13 slidably engaging slider 8.

The rotation-inhibiting element 13 has at least one rod 14, two diametrically opposite rods 14 in the example shown, extending parallel to the longitudinal extension of screw 4 starting from a base portion 15 provided with a peripheral toothing 15 a engaging a corresponding mating toothing 15 b formed in housing 2 at the second end 2 b.

The rotation-inhibiting element 13 is therefore locked against rotation in housing 2.

At least one longitudinal groove 16 is defined between rods 14 and in the example shown it consists of a diametrical through cut in which the attachment portions 12 a of the radial projections 12 of slider 8 slidably engage at diametrically opposite positions. Engagement of the radial projections 12 in the longitudinal groove 16 prevents rotation of slider 8 with respect to the rotation-inhibiting element 13, while allowing mutual sliding in the longitudinal direction.

Extending between rods 14, at an opposite position relative to the base portion 15, is an end portion 17 rotatably engaging one end of screw 4, so as to ensure axial alignment of the latter.

In addition, the rotation-inhibiting element 13 and screw 4 may be provided to be longitudinally housed in a tubular skirt 18 coaxially carried by slider 8, substantially extending over the same length as the length of the threaded portion 5 of screw 4.

Advantageously, housing 2, as well as the closing cap 3, operating knob 7 and other inner components of case 1, can be made of transparent plastic material so that the stick of product 9 contained in the housing itself can be made directly visible from the outside.

Advantageously, arrangement of the rotation-inhibiting element 13 between slider 8 and screw 4 makes it possible to keep an inner cylindrical surface 2 c in housing 2 in a smooth and continuous condition, i.e. without discontinuities that can offer an anesthetic appearance and/or impair the sight of stick 9.

Advantageously, also the screw 4, rotation-inhibiting element 13 and skirt 18 are concealed to an observer's sight at least in the rest condition, as they are housed in a cavity 9 c longitudinally and coaxially formed in stick 9.

The case according to the invention allows a product in stick form to be packaged by directly pouring the pasty product in a melted state into housing 2, the slider 8 being in the rest position, said product in stick form 9 being subsequently solidified by cooling inside the housing itself.

Alternatively, the pasty product in stick form 9 with the longitudinal cavity 9 c open at least towards the end of base 9 a of the product itself, can be conventionally formed at the outside of housing 2, to be then longitudinally introduced into the case itself concurrently with engagement of the base end 9 a with slider 8. 

1. A mechanical extraction case for pasty products in stick form, comprising: a tubular housing (2); a slider (8) designed to engage a pasty product in stick form (9) and slidably engaged in the tubular housing (2); a lead screw (4) coaxially extending along the housing (2) through a through opening (11) formed in the slider (8) and operatively engaging the slider itself to translate it along the housing (2) following a rotation imparted to the lead screw (4); characterized in that a rotation-inhibiting element (13) is radially interposed between the lead screw (4) and slider (8), which element (13) is locked against rotation in the housing (2) and slidably engages the slider (8).
 2. The case as claimed in claim 1, wherein the slider (8) at said central opening (11) has at least one radial projection (12) operatively in engagement with a threaded portion (5) of the lead screw (4).
 3. The case as claimed in claim 2, wherein the rotation-inhibiting element (13) has at least one longitudinal groove (16) slidably passed through by the radial projection (12) of the slider (8).
 4. The case as claimed in claim 1, wherein the rotation-Inhibiting element (13) has a base portion (15) fastened into the housing (2) and at least one rod (14) extending from the base portion (15) parallel to the longitudinal extension of the lead screw (4).
 5. The case as claimed in claim 4, wherein the rod (14), on the side opposite to the base portion (15), carries an end portion (17) rotatably engaging one end of the lead screw (4).
 6. The case as claimed in claim 1, wherein the rotation-inhibiting element (13) is housed in a cavity (9 a) longitudinally formed in the pasty product in stick form (9).
 7. The case as claimed in claim 1, wherein the slider (8) coaxially carries a tubular skirt (18) longitudinally housing the rotation-inhibiting element (13) and the lead screw (4).
 8. The case as claimed in claim 7, wherein the tubular skirt (18) extends over substantially the same length as the length of a threaded portion (5) of the lead screw (4).
 9. The case as claimed in claim 1, wherein the tubular skirt (1.8) extends in a cavity (9 c) longitudinally formed in the pasty product in stick form (9).
 10. The case as claimed in claim 1, wherein at least said tubular housing (2) is made of transparent material.
 11. The case as claimed in claim 1, wherein said tubular housing (2) has a smooth and continuous inner cylindrical surface (2 c). 